Dental matrix-retainer.



C. J. EMERSON.

DENTAL MATRIX RETAINER.

APPLICATION r1110 OCT. 17. I914 Patented Aug. 24:, 1915.

CHARLES tr. nnnason, or OMAHA, NEBRASKA.

DENTAL MATRIX-RETAINER.

Application filed October 17, 1914.

To all whom it may concern: I 7

Be it known that I, CHARLES J. EMERSON,

a citizen of the United States, residing in Omaha, in the county ofDouglas and State of Nebraska, have invented certain new and usefulImprovements in Dental Matrix-Retainers, and have described-the same inthe following specification, illustrated by the accompanying drawings.

My invention relates to that class of re tainers which havejaws and areused by dentists in connection with band matrices for the purpose ofholding those matrices to the teeth while the latter are being filled.Such a matrix, it will be understood, comprises a thin strip of easilyflexible and practically inelastic metal, encircling or partlyencircling a tooth in the human mouth It is applied with recognizedadvantage in case the cavity to be filled is located on the approximalsurface of an upper or lower front tooth from which a portion of thelingual surface has been lost.

It is the object of the invention to adapt a retainer of the specifiedclass to grip'by and between its jaws immediately, in each instance, asingle tooth, to the exclusion of all others, and hold the matrix tothat tooth; to avoid thereby the-production of stresses tending to movethe teeth relatively to each other; to prevent the discomforts thatcommonly result from such stresses; and incidentally to simplify theconstruction of the retainer and render the appliance convenientlycompact, and easy to be applied and adjusted. To accomplish this objectI incorporate in my improved retainer, as parts thereof, a pair ofcoacting hinged jaws which are adapted to engage respectively the libialand the palatal or lingual surfaces of the tooth, means for adjustablyclosing and releasing the jaws, and a setscrew for engagement with thematrix. I

In the accompanying drawings, illustrating the best manner in which Ihave contem plated applying the principles of my invention, Figure 1 isaside elevation of a retainer which is constructed in accordance withthese principles and operatively applied to a tooth and matrix'which areshown in section. Fig. 2 is a front elevation of the same matrix andretainer, applied to a defective tooth standing between other teeth.Fig. 3 is a detail, being a plan of the flat matrix blank before bendingto fit the tooth. Fig. 4: is a perspective view showing a Specificationof Letters Patent. Patented Aug. 24, 1915.

Serial No. 867,111.

matrix formed against one tooth, and having its band wrapped aroundanother tooth. Fig. 5 is a perspective View of the complete retaineralone.

In the illustrated specimen of the invention the jaws are denoted by thenumerals 1 and 2 respectively. They are hinged together at one end bythe pivotal pin 3, are provided with inwardly directed terminal teeth,or points, 4t and 5, respectively, and are radially of unequal length.They are connected by the transverse arm 6, which projects from thelonger and bent jaw 1, spans the space between the jaws, extends freelythrough a slot 12 in the shorter jaw, and is terminally provided with ascrew thread and with the thumb-nut 7 for drawing the jaws together. Thepointed screw 8, having a knurled head,works in a screwhole through thejaw l toward and from the jaw 2. This screw and the screw arm 6, as wellas both of the described jaws, are disposed with their longitudinal axesin a single plane normal to the axis of the pin 3.

The matrix-forming strip, shown fiat in Fig. 3, may advantageously bestamped from a thin sheet of German silver. Operatively the dentistbends or wraps this strip against or around an affected tooth 9 in thedesired 3 form of the matrix ll, encircling the tooth more or lesscompletely as may be required. Then he applies the jaws likecxternalcalipers, with the points 4: and 5 at the margins of the gums 10, asshown in Fig. l; and clamps the j aws immovably to the tooth betweenthem by turning the nut 7. Then by turning the screw 8, and withoutdisturbing the grip or position of the jaws 1 and 2 upon the tooth, headvances the screw point against the side of the matrix or retracts thatpoint, as occasion may require; by the advance he compresses a portionof the matrix between the screw and the tooth, and thereby plasticallyshapes the matrix to the contiguous tooth surface; by the advance helikewise secures the matrix to its seat upon the tooth with greater orless firmness of pressure at difierent times, according 'to therequirements of the work; by the retraction of the screw he relaxes thepressure of the matrix upon the tooth, for the purpose of exposing themargin of the tooth cavity,

or for other purposes, as may be desired.

In this way the above stated object of the invention is accomplished inall its branches.

I claim 1. A dental matrix retainer of the speci fied class, comprisinga pair o-f tooth-hol-ding jaws hinged together at one end, a transversearm projecting from one of the jaws--and working through a slot in theother jaw, a nut on the'outer'end of tlriegarm; and a screw. carried byone of the jaws and placed diagonally with its tip adapted to impiiige'npon" the matrix onthe tooth.

2. A denmmmix' retainer oifthespcified' class, comprising pairofcoactiing hinged jaws adapted to engage opposinggurin s of the toothwhich is to be filled, means for operating thejaiwsto clam that "toothbe the jaws?andpositionedfsdag 5 form ,tween prolonged ofthe screw;

the longitudinal akis of the to oth 'an'acute otajiaXisofthe hinges-andadapted to 611? gage at a greater distance from that axis matrix on thetooth so'11e1d;'-

" -In testimony whereof "I' subscribe this specification in"the presenceof two nes'ses.

" Witnesses: 1 H v I WmLARo-EDDY;

I. S. LEAVITT,

oH-ARLEs 11.: nMERson;

-and a screw working through I one of the jaws at a distance from thepiv-

